// 在当前目录运行以下命令对 intset 包进行测试：
// $ go test -v ./intset
// 输出：
// === RUN   Test_Has
// --- PASS: Test_Has (0.00s)
//     intset_test.go:50: After Has, set.Has(1) = true, myset.Has(1) = true, ok
//     intset_test.go:50: After Has, set.Has(15) = true, myset.Has(15) = true, ok
// === RUN   Test_Add
// --- PASS: Test_Add (0.00s)
//     intset_test.go:60: After Add, set = {1 15}, myset = {1 15}, ok
// === RUN   Test_UnionWith
// --- PASS: Test_UnionWith (0.00s)
//     intset_test.go:76: After UnionWith, set = {1 15 30 45}, myset = {1 15 30 45}, ok
// PASS
// ok      _/D_/workspace/goex/课后习题代码/ch11/intset    0.189s